An electrochemical generator is an electricity producing device in which chemical energy is converted into electrical energy. The chemical energy is made up of electrochemically active compounds deposited on at least one face of electrodes positioned in the electrochemical generator. The electrical energy is produced by electrochemical reactions during the discharge of the electrochemical generator. The electrodes, which are positioned in a container, are electrically connected to current output terminals, which ensure electrical continuity between the electrodes and an electricity consumer with which the electrochemical generator is associated. The positive and negative current output terminals may be fastened either on the walls of opposite faces of the container of the electrochemical generator or on the wall of a same face of the container.
Several electrochemical generators can be connected together in series or in parallel as a function of the rated operating voltage of the electricity consumer and the quantity of energy that is planned to be provided to that consumer. The electrochemical generators are then placed in a shared housing, generally made up of a box and a cover, and the assembly of the housing and the plurality of electrochemical generators it contains are generally referred to as a battery. For convenience of electrical connection between electrochemical generators placed in a battery, the positive and negative output current terminals are often fixed on the wall of a same face of the container.
An anomaly in the operation of the battery may be caused by the malfunction of one of the electrochemical generators (short circuit, overload, etc.) or by an outside disturbance (impact, temperature increase, etc.) or by a failure of the electronic system managing the charge state or other parameters of the generators of the battery.
For example, when a lithium electrochemical generator is subjected to an overload, its temperature increases. The temperature increase causes an increase in the charge current, which further favors the temperature increase. If the generator does not have a sufficient cooling system to discharge the emitted heat, it is in a thermal runaway state: the temperature increase is fed by the generator itself. The uncontrolled increase in the temperature of the generator causes the generation of gases and their expansion inside the container of the generator. This expansion can cause an increase in the inner pressure inside the generator, which will open the gas discharge safety system. In the event hot gases are released, the temperature of which may reach 650° C., these gases come into contact with other generators of the battery. There is then a risk of the thermal runaway phenomenon spreading to all of the generators of the battery, which leads to the total destruction of the battery. This risk is particularly high in the case of generators of the lithium-ion type.
Technical solutions are known for cooling of the gases using the battery system alone. However, these do not currently enable sufficient cooling of the gases for the gases to be cooled enough at the output of the gas discharge safety system, which generally comprises a vent hole. These flames are then dangerous for the equipment integrating the battery as well as its users.
The aim of the invention is to propose a safety device making it possible first to contain any gases emitted by the lithium electrochemical generators, then to discharge them outside a compartment so as to avoid any contamination of that compartment as well as risks of self-ignition of the emitted gases.